void setup() {
  // put your setup code here, to run once:
  pinMode(2,OUTPUT);
  
}

void loop() {
  // put your main code here, to run repeatedly:

  digitalWrite(2,HIGH);  //设置引脚为高低电平j
  delay(1000);
  digitalWrite(2,LOW);  //设置引脚为高低电平j
  delay(1000);
}
